Pedicular facet fusion screw with plate

ABSTRACT

Spinal implants and methods for spinal stabilization and/or fusion are provided. Exemplary implants described herein can be configured for delivery to a facet joint to stabilize and/or fuse the facet joint, and can optionally be anchored within the pedicle for added fixation. The implant can optionally include a fusion-promoting bioactive material thereby providing a single device capable of spinal stabilization and/or fusion. Furthermore, a method of placing such an implant within a facet joint is provided.

FIELD

The present invention relates to methods and devices for spinalstabilization and fusion, and particularly to stabilization and fusionof a facet joint.

BACKGROUND

The vertebrae in a patient's spinal column are linked to one another bythe intevertebral disc and the facet joints. This three joint complexcontrols the movement of the vertebrae relative to one another. Eachvertebra has a pair of articulating surfaces located on the left side,and a pair of articulating surfaces located on the right side, and eachpair includes a superior articular surface and an inferior articularsurface. Together the superior and inferior articular surfaces ofadjacent vertebrae form a facet joint. Facet joints are synovial joints,which means that each joint is surrounded by a capsule of connectivetissue and produces a fluid to nourish and lubricate the joint. Thejoint surfaces are coated with cartilage allowing the joints to move orarticulate relative to one another.

Diseased, degenerated, impaired, or otherwise painful facet jointsand/or discs can require surgery to restore function to the three jointcomplex. In the lumbar spine, for example, one form of treatment tostabilize the spine and to relieve pain involves fusion of the facetjoint. There are various techniques for stabilizing and treating thefacet joint. However, current instrumentation can limit the availabletechniques by requiring specific insertion trajectories and/or byproviding limited options for securement to the various anatomiessurrounding the facet joint.

Accordingly, there is a need for instrumentation and techniques that canfacilitate insertion and securement of implants in various orientationsand to varied bony anatomies to facilitate the safe and effectivestabilization of facet joints.

SUMMARY

Spinal implants and methods relating to stabilization and/or fusion of afacet joint. In general, the implant functions as a sort of mechanicalstaple and/or key that prevents sliding motion between the diarthroidalsurfaces of the facet joint. Further, the spinal implant can include afusion-promoting bioactive material thereby providing for a singlespinal implant capable of allowing for both fixation and fusion of adesired facet joint. Various aspects of the implants and methods aresummarized immediately below.

In one aspect, the spinal implant can include a cannulated elongatemember having a proximal head with a shank extending distally therefrom.The shank can have a thread extending over at least a portion thereof,and a portion thereof can remain unthreaded. In some embodiments, theproximal head can be substantially spherical with an annular rimextending proximally therefrom. The spinal implant can also include astabilization member configured to rotate in all directions relative tothe proximal head of the elongate member. In another embodiment, thestabilization member can have a proximal portion with an expandablediameter that is configured to seat the proximal head of the elongatemember. The annular rim can be configured to limit rotation of thestabilization member to prevent the stabilization member from extendingover a proximal surface of the proximal head.

The stabilization member can have many configurations and can include adistal portion having at least one feature configured to engage a bonyportion of a facet joint. For example, the distal portion can include aplurality of bone piercing tines configured to engage a bony portion ofa facet joint. An outer surface of the plurality of bone piercing tinescan be angled inward toward the shank. The proximal portion of thestabilization member can include a plurality of arms configured toexpand to engage the proximal head.

The proximal head can also have many configurations. For example, theproximal head can include an expandable opening formed in a proximalportion thereof and concentrically aligned with the annular rim. In someembodiments, the expandable opening can be configured to receive a setscrew. The proximal head and the annular rim can include at least oneslit formed in a sidewall thereof configured to allow the proximal headto expand to receive a set screw. The proximal head and the annular rimcan be configured to expand to engage and interlock with thestabilization member when a set screw is disposed within the expandableopening. The proximal head can also include a driving feature disposeddistally to the expandable opening and configured to receive a drivingtool to facilitate insertion of the elongate member. Any portion of theimplant can include a fusion-promoting bioactive material.

In another aspect, a spinal implant is provided and can include a distalbone engaging shank having a thread extending over at least a portionthereof. A head can be formed on a proximal end of the shank and can becoupled to a stabilization member. The head can be configured forrotational movement in all directions relative to the stabilizationmember, and a rotation stop can be formed on a proximal portion of thehead and configured to engage a proximal portion of the stabilizationmember to limit rotational motion of the head relative to thestabilization member. In some embodiments, the rotation stop can be anannular rim extending proximally from the head. The head can optionallyinclude an expandable opening formed therein configured for receiving aset screw. The head can be configured to expand and interlock with thestabilization member when a set screw is threaded into the expandableopening.

The stabilization member can have many configurations and can include,for example, an annular expandable sidewall configured to receive thehead. The sidewall can have a radius greater than a radius of theannular rim, and at least a portion of the annular expandable sidewallcan be configured to engage at least a portion of the annular rim tolimit rotational motion of the head relative to the stabilizationmember. The stabilization member can also include a plurality of boneengaging tines extending distally from the annular expandable sidewalland configured to engage bone. The stabilization member can have alength and a width orthogonal to the length, the length being greaterthan the width. In one embodiment, the stabilization member can includea plurality of expandable arms extending proximally therefrom in asubstantially circular configuration. The expandable arms can beconfigured to receive the head and a central axis of the expandable armscan be offset from a central axis of the stabilization member. In someembodiments, the stabilization member can include a bend zone formedtherein configured to allow one side of the stabilization member to bendrelative to an opposite side of the stabilization member to conform to abone surface. The stabilization member can also include a cavity formedtherein configured to be filled with a fusion-promoting bioactivematerial.

In a further aspect, a spinal implant is provided and can include anelongate member having a distal shank with a thread extending over atleast a portion thereof and a substantially spherical proximal headcoupled to a stabilization member. The stabilization member can beconfigured to allow rotation of the elongate member in all directionsrelative to the stabilization member. In some embodiments, thestabilization member can include a plurality of expandable arms definingan opening for receiving the proximal head, and can be movable between afirst diameter which is less than a diameter of the proximal head and asecond diameter which is greater than the diameter of the proximal head.

In one embodiment, the proximal head can include an annular rimextending proximally therefrom and configured to engage the plurality ofexpandable arms to limit rotation of the elongate member. Thestabilization member can also include a plurality of bone engaging tinesextending distally therefrom. The proximal head can optionally beexpandable, and the plurality of expandable arms can be disposed in asubstantially circular configuration defining a central axis. In anotherembodiment, the stabilization member can include a lateral extensionsuch that the central axis of the expandable arms are offset from acentral axis of the stabilization member. The stabilization member canfurther include a bend zone disposed between the lateral extension andthe expandable arms. The bend zone can be configured to allow thelateral extension to be bent at an angle relative to the expandablearms.

In another aspect, a spinal implant is provided and can include acannulated elongate member having a first bone engaging portion with afirst diameter and a second bone engaging portion with a seconddiameter. While the first and second bone engaging portions can have anydiameter, in some embodiments, the first diameter can be greater thanthe second diameter. The first bone engaging portion can be configuredfor insertion into a facet joint and the second bone engaging portioncan be configured for insertion into a pedicle. In some embodiments, atleast one of the first and second bone engaging portions can have atleast one opening formed in a sidewall thereof and configured to receivean osteoconductive composition.

The spinal implant can include a stabilization member configured to seatthe elongate member. The stabilization member can have a firstexpandable portion configured to engage a portion of the elongate memberand a second bone engaging portion having a plurality of bone engagingtines extending therefrom. Each bone engaging tine can be angled towarda central axis of the elongate member. In one embodiment, at least oneof the first and second bone engaging portions can have a plurality ofopenings formed in the sidewall thereof. Each of the plurality ofopenings can be a different shape.

The elongate member can include a proximal head with a shank extendingdistally therefrom. The shank can have a thread extending over at leasta portion thereof. The first expandable portion of the stabilizationmember can include a plurality of substantially flexible arms arrangedin a circular configuration. Each arm can be separated from adjacentarms by a slit configured to allow expansion and contraction of thearms. In some embodiments, the plurality of substantially flexible armsare configured to receive a proximal head of the elongate member and toallow rotation in all directions of the proximal head relative thereto.The stabilization member can optionally include a lateral extension suchthat a central axis of the first expandable portion is offset from acentral axis of the stabilization member. The lateral extension can beconfigured to bend relative to the first expandable portion to conformto a bony surface adjacent to a facet joint as the elongate member ispositioned within the facet joint.

In a further aspect, a spinal implant is provided and can include anelongate member having a proximal head and a bone engaging shankextending distally from the proximal head. The proximal head can beconfigured for rotational movement in all directions within astabilization member. In some embodiments, the shank can have at leastfirst and second openings formed in a sidewall thereof and can beconfigured to receive an osteoconductive composition. The shank canfurther have a thread extending over at least a portion thereof, and afirst portion with a first major diameter and a second portion with asecond major diameter, in which the first major diameter can be greaterthan the second major diameter.

In one embodiment, the first and second openings can be disposed along alongitudinal axis of the elongate member. The first and second openingscan have many different configurations including different sizes anddifferent shapes. The spinal implant can also include a stabilizationmember configured to seat the elongate member. In some embodiments, thestabilization member can include a stabilizing plate portion having aplurality of bone engaging tines extending distally therefrom forpiercing bone. Further, the stabilization member can include astabilizing plate portion having a plurality of expandable armsextending proximally therefrom configured to receive the proximal headof the elongate member.

While the stabilizing plate portion can have many configurations, in oneembodiment, the stabilizing plate portion can have a length extendingbetween first and second opposed sides and a width extending betweenthird and fourth opposed sides, wherein the length is greater than thewidth. The stabilizing plate portion can optionally include an extensionmember extending distally from one of the first and second opposedsides. The extension member can have a length greater than a length ofthe plurality of bone engaging tines. In another embodiment, thestabilizing plate portion can include at least one bendable regiondisposed thereon such that the stabilizing plate portion is bendablealong a line orthogonal to the length of the stabilizing plate portion.

In one exemplary embodiment, the stabilization member can include atranslation plate disposed adjacent to the stabilizing plate portion.The translation plate can have a plurality of expandable arms extendingproximally therefrom configured to receive the proximal head of theelongate member and to allow rotational movement of the proximal head inall directions relative to the stabilization member. The translationplate can be configured to translate laterally with the elongate memberrelative to the stabilizing plate portion along the length of thestabilizing plate portion.

In other embodiments, the stabilizing plate portion can include aplurality of expandable arms extending proximally therefrom defining afirst opening disposed adjacent to one of the first side and the secondside and offset from a central axis of the stabilizing plate portion, aswell as a second opening formed on the first or second side opposite tothat of the first opening. The expandable arms can be configured toreceive the proximal head, and the first opening can be configured toreceive the elongate member. The second opening can be configured toreceive the second elongate member therethrough. In some embodiments,the second elongate member can be a lamina screw configured to engage alamina while the elongate member is engaged within a facet joint. Thestabilizing plate portion can also optionally include a first portionand a second portion, the first and second portions being coupledtogether by an adjustable coupling. The adjustable coupling can beconfigured to allow translation of the first portion relative to thesecond portion and bending of the first portion relative to the secondportion.

In another aspect, a method of implanting a spinal implant is providedand can include providing an elongate member having a first boneengaging portion and a second bone engaging portion. At least one of thefirst and second bone engaging portions can have at least one openingformed therein for receiving an osteoconductive composition. The methodcan further include packing an osteoconductive composition into theopening and surgically delivering the elongate member into a vertebrasuch that the first bone engaging portion is disposed within a facetjoint and the second bone engaging portion is disposed within a pedicle.The method can also include engaging a stabilization member coupled tothe elongate member to a bony portion of a vertebra adjacent to thefacet joint in which the elongate member is disposed. Further, thestabilization member can be bent to engage a bony portion of a vertebraadjacent to the facet joint in which the elongate member is disposed.

In some embodiments, the method can further include delivering a firstspinal implant to a first facet joint and a second spinal implant to asecond, corresponding facet joint at the same level of a spine. Thesurgically delivering step can be conducted in a minimally invasivesurgical procedure. A lamina screw can also be delivered to a vertebrallamina through an opening in the stabilization member to provideadditional stabilization for the elongate member disposed within thefacet joint.

These aspects and others will be described in detail below.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be more fully understood from the following detaileddescription taken in conjunction with the accompanying drawings, inwhich:

FIG. 1A is a cross-sectional view of an exemplary implant disposedwithin a facet joint;

FIG. 1B is a perspective view of the spinal implant of FIG. 1A;

FIG. 2A is a perspective view of an exemplary spinal implant having anelongate member and a stabilization member;

FIG. 2B is a side view of a portion of the implant of FIG. 2A;

FIG. 3A is a side view of one embodiment of a stabilization member;

FIG. 3B is a side view of the stabilization member of FIG. 1A;

FIG. 3C is side view of another embodiment of a stabilization member;

FIG. 4A is a perspective view of one embodiment of a spinal implanthaving an expandable head;

FIG. 4B is a side view of an exemplary elongate member having openingsformed therein for receiving a bio-active fusion promoting composition;

FIG. 5 is a side view of an exemplary elongate member having openingsformed therein for receiving a bio-active fusion promoting composition;

FIG. 6A is a side view of an exemplary elongate member having a shankwith two different major diameters;

FIG. 6B is a perspective view of the elongate member of FIG. 6A;

FIG. 7 is a side view of another embodiment of an elongate member havinga distal portion for insertion into a pedicle and a proximal portion forinsertion into a facet joint;

FIG. 8A is a side view of one embodiment of a laterally extendedstabilization member;

FIG. 8B is a top view of the stabilization member of FIG. 8A;

FIG. 9A is a side view of another embodiment of a laterally extendedstabilization member;

FIG. 9B is a top view of the stabilization member of FIG. 9A;

FIG. 10A is a side view of one embodiment of a stabilization memberhaving an extension portion;

FIG. 10B is a perspective view of the stabilization member of FIG. 10A;

FIG. 11A is a side view of another embodiment of a stabilization memberhaving a translatable portion;

FIG. 11B is a front view of the embodiment of FIG. 11A;

FIG. 11C is a side view of the embodiment of FIG. 11A having an elongatemember disposed therein;

FIG. 11D is a top view of the embodiment of FIG. 11C;

FIG. 12A is a perspective view of an exemplary implant having alaterally extended stabilization member with a lamina screw;

FIG. 12B is an alternate perspective view of the stabilization member ofFIG. 12A;

FIG. 12C is a side view of the lamina screw of FIG. 12A;

FIG. 12D is a representation of the implant of FIG. 12A positionedwithin the facet joint;

FIG. 12E is a top view of the implant of FIG. 12A;

FIG. 13A is a perspective view of another embodiment of an implanthaving a lateral adjustment mechanism;

FIG. 13B is a bottom view of the implant of FIG. 13A;

FIG. 14A is a top view of one embodiment of a stabilization memberconfigured to allow lateral adjustment;

FIG. 14B is a side view of the stabilization member of FIG. 14A;

FIG. 14C is a side view of an elongate member configured to be insertedwithin the stabilization member of FIG. 14A;

FIG. 14D is a top view of the elongate member of FIG. 14C;

FIG. 15A is a perspective view of exemplary implants disposed within afacet joint in a trans-facet orientation;

FIG. 15B is a perspective view of exemplary implants disposed within afacet joint in an intra-facet orientation; and

FIG. 15C illustrates a trajectory of an exemplary implant through thefacet joint and into the pedicle.

DETAILED DESCRIPTION OF THE INVENTION

Certain exemplary embodiments will now be described to provide anoverall understanding of the principles of the structure, function,manufacture, and use of the devices and methods disclosed herein. One ormore examples of these embodiments are illustrated in the accompanyingdrawings. Those skilled in the art will understand that the devices andmethods specifically described herein and illustrated in theaccompanying drawings are non-limiting exemplary embodiments and thatthe scope of the present invention is defined solely by the claims. Thefeatures illustrated or described in connection with one exemplaryembodiment may be combined with the features of other embodiments. Suchmodifications and variations are intended to be included within thescope of the present invention.

In general, spinal implants and methods for spinal stabilization and/orfusion are provided. Exemplary implants described herein can beconfigured for delivery to a facet joint to stabilize and/or fuse thefacet joint, and can optionally be anchored within the pedicle for addedfixation. As shown in FIGS. 1A and 1B, an exemplary implant 2 cangenerally include an elongate member 4, such as a bone screw orfastener, polyaxially coupled to a stabilization member 6, such as abone engaging washer. The elongate member 4 can be disposed within thefacet joint as shown, while the stabilization member 6 can engage anouter portion (e.g., an edge) of a facet joint to co-join the facetfaces. In an exemplary method of using the implant 2, the elongatemember 4 and the stabilization member 6 can be delivered to and insertedwithin and/or around the facet joint in a desired configuration and at adesired angle. The stabilization member 6 and the elongate member 4 canbe rotated polyaxially (e.g., in all directions) relative to one anotherto achieve an optimal angle within and/or around the facet joint beforebeing secured thereto. For example, the relative angular orientation ofthe elongate member 4 and the stabilization member 6 can thus beadjusted as needed to accommodate different positions within the facetjoint, as well as various shaped anatomical structures, thereby allowingfor a better fit of the implant 2.

Any of the exemplary implants described herein can also have featuresthat allow for variable placement of a stabilization member and/or anelongate member within and/or around the facet joint to facilitate facetstabilization and/or fusion. For example, exemplary stabilizationmembers can have laterally extended portions and/or bendable portionsthat allow for the placement of additional securement components, andthat generally allow for more flexibility in placement of the implant inand around the facet joint. In addition, exemplary implants can haverepositioning mechanisms and/or adjustable couplings associatedtherewith that allow variability in the anchoring trajectory of theimplant. Various exemplary embodiments of elongate members andstabilization members for use in these ways will be described herein.

Referring now to FIGS. 2A and 2B, a more detailed exemplary embodimentof a spinal implant 10 is provided. The spinal implant 10 can include anelongate member 14 coupled to a stabilization member 12. The elongatemember 14 can extend from a distal end 16 to a proximal end 18. A head20 can be formed on the proximal end 18, and a shank 22 can extenddistally from the head 20. The stabilization member 12 can couple to thehead 20 of the elongate member 14 by circumferentially encircling thehead 20. The elongate member 14 can generally be configured to rotatepolyaxially relative to the stabilization member to allow thestabilization member 12 to adapt to various anatomical structures duringplacement within the facet joint.

The elongate member 14 can take many different forms, including theforms of a pin, a dowel, a plug, a beam, a post, a threaded post, abolt, an expansion barrel, a pop-rivet, a staple, an anchor, a screw,etc. In the illustrated embodiment, the elongate member 14 is in theform of a bone screw configured for placement within a facet joint. Theelongate member 14 can be cannulated such that a lumen 15 extendsthrough the elongate member 14 along a central longitudinal axis of theelongate member 14. The lumen 15 can be configured to receive a guidewire, such as a Kirschner wire, to help facilitate insertion of theimplant 10 and/or can be configured for packing with a bioactiveosteoconductive composition, as will be described in more detail below.In other embodiments, the elongate member 14 can be solid, without alumen 15 extending therethrough.

The elongate member 14 can also include one or more features tofacilitate engagement between the shank 22 and bone. For example, athread 24 can extend around at least a portion of the shank 22 of theelongate member 14 to facilitate engagement between the shank 22 andbone. In some embodiments, at least a portion 25 of the shank 22 canremain unthreaded. As will be appreciated by those skilled in the art,any portion of the shank 22 can be threaded or unthreaded. For example,all of the shank 22 can be threaded or all of the shank 22 can remainunthreaded, and the thread 22 can be continuous or non-continuous.Further, the shank 22 can include more than one thread, including twohelical threads and/or two or more threads having different pitches,different major diameters, etc. The shank 22 can have a major diameterD_(M) defined by the outer diameter of the threads, and a minor diameterD_(m) defined by the diameter of the unthreaded shank. In theillustrated embodiment, the thread 22 can have a substantially constantthread crest height, thickness, and pitch along a length of the shank22. As will be appreciated by those skilled in the art, threadparameters can be optimized for a particular embodiment to providedesired engagement characteristics in the bone.

The head 20 of the elongate member 14 can also have many configurations,and can have any size and shape as desired. In the illustratedembodiment, the head 20 is substantially spherical with a diameterlarger than the major diameter D_(M) of the shank 22. The head 20 canalso be substantially cylindrical, rectangular, etc. and can have adiameter smaller than a diameter D_(M) of the shank. The head 20 canhave an opening 26 formed in a proximal end thereof that can beconfigured for receiving a driving tool to facilitate insertion of theelongate member 14. For example, the opening 26 can have features formedtherein that will complement features on a driving tool to facilitaterotation of the elongate member 14 into bone. The head 20 can alsoinclude an annular rim 28 extending proximally therefrom. In theillustrated embodiment, a circumference of the annular rim 28 definesthe opening 26. The annular rim 28 can have any height and widthdesired, and can have a circumference and/or diameter as is appropriatefor a particularly sized head 20. For example, the annular rim can havea diameter in the range of about 3 mm to about 10 mm and a height in therange of about 0.25 mm to about 5 mm. In some embodiments, the height ofthe annular rim 28 can be sufficient to limit rotation of the elongatemember 14 relative to the stabilization member 12 by preventing thestabilization member 12 from rotating over the proximal end 18 of theelongate member 14, as will be described in more detail below.

The stabilization member 12 can generally be configured to stabilize theelongate member 14 when it is engaged with bone and to preventover-insertion of the elongate member 14. As shown in FIGS. 2B and 3B,the stabilization member 12 can have a substantially circular and/orpartial spherical shape for encircling the substantially spherical head20 of the elongate member 14. The stabilization member 12 can include astabilizing plate portion portion 30 having an elongate member receivingportion 34 extending proximally therefrom for receiving the head 20 ofthe elongate member 14, and a bone engaging portion 36 extendingdistally therefrom for engaging bone. The stabilizing plate portion 30can be a plate-like member, which may or may not be continuous, and thatextends in a lateral plane orthogonal to a central axis CA of thestabilization member 12. An opening 32 can extend through a center ofthe stabilization member 12 and can be concentrically aligned with acentral axis CA of the stabilization member 12.

The elongate member receiving portion 34 extending proximally from thestabilization member 12 can have any configuration suitable forreceiving the head 20 of the elongate member 14. In the illustratedembodiment, the elongate member receiving portion 34 can have a partialspherical shape so that it can receive the substantially spherical head20 of the elongate member 14. More particularly, the elongate memberreceiving portion 34 can be composed of one or more flexible and/orexpandable arms 38 that extend proximally from the stabilizing plateportion 30. In the illustrated embodiment, a plurality of the flexibleand/or expandable arms 38 extend proximally from the stabilizing plateportion 30 and are each separated by a slit or opening 40 to allowexpansion and contraction thereof. The arms 38 can provide thestabilization member 12 with a “snap-fit” onto the spherical head 20 andcan allow polyaxial movement of the stabilization member 12 relative tothe head 20. The arms 38 can have any shape and configuration desired,but in the illustrated embodiment, each arm 38 has a substantiallyrounded wedge shape such that an inner surface 56 of the arm 38 iscurved to match the curve of the substantially spherical head 20 of theelongate member 14. An outer surface 58 of the arm 38 can curve distallyoutward in a wedge configuration. A distal portion of each arm 38 can bethinned to form a bend zone 58 to provide the arms 38 with flexibilitysuch that the arms 38 flex, expand, and contract, about the bend zone58.

As noted above, the stabilization member 12 can also have a boneengaging portion 36 extending therefrom. The bone engaging portion 36 ofthe stabilization member 12 can have any configuration suitable forengaging, gripping, piercing, and/or penetrating bone. One or morefeatures can extend distally from the stabilizing plate portion 30 tofacilitate engagement with the bone. In the illustrated embodiment, aplurality of bone engaging tines 42 extend distally from the stabilizingplate portion 30 and can be configured for engaging, gripping, piercing,and/or penetrating bone. The tines 42 can be of different sizes andshapes, and can be adapted to perform different functions as needed. Inthis embodiment, the tines 42 can decrease in width as they extenddistally until they form a bone piercing and/or penetrating tip 44.

The tines 42 extending from the stabilizing plate portion 30 can bearranged in many configurations. In some embodiments, a proximal portion46 of the tine 42 can extend distally and substantially orthogonallyfrom the stabilizing plate portion 30 such that the tines 42 have anouter diameter substantially the same as an outer diameter of thestabilizing plate portion 30. An outer surface 48 of a distal portion 54of the tine 42 can bend inward toward the shank 22 such that the outersurface 48 of the distal portion 54 is angled relative to the outersurface 50 of the proximal portion 46, for example at an angle in arange of about 5 degrees to about 60 degrees, and more preferably in arange of about 10 degrees to about 45 degrees. An inner surface 52 ofthe tine 42 can remain at a substantially constant angle (i.e.,substantially orthogonal to the stabilizing plate portion 30) or it cancurve inward slightly toward the shank 22 with a radius of curvature inthe range of about 5 mm to about 20 mm, for example about 13 mm, as itextends distally from the stabilizing plate portion 30 across theproximal portion 54 and the distal portion 46.

The structure of the tines 42 provide easier bone penetration and a moresecure engagement between the bone and the stabilization member. Inparticular, as the bone engaging tines 42 are driven into bone, theangled outer surface 50 of the tines 42 will cause the stabilizationmember 12 to close down and inward to provide a more secure purchasewithin bone. In use, when the elongate member 14 is disposed within afacet joint, a first tine 42 and/or first set of tines 42 can pierce atop vertebra (or top facet face) while a second tine 42 and/or secondset of tines 42 can pierce an adjacent, bottom vertebra (or opposingfacet face). As such, the stabilization member 12 can effectively act ina staple-like manner securing the implant 10 within the facet joint.

As noted above, the implant 10 can include features to limit rotation ofthe elongate member 14 relative to the stabilization member 12. Forexample, as also noted above, the head 20 of the elongate member 14 caninclude an annular rim 28 extending proximally therefrom that can beconfigured to limit rotation of the elongate member 14 relative to thestabilization member 12 by preventing the stabilization member 12 fromrotating over the proximal end 18 of the elongate member 14. When thestabilization member 12 is coupled to the head 20 of the elongate member14, it can rotate polyaxially (i.e., in all directions) relative to theelongate member 14 due to the complementary spherical shape between thehead 20 of the elongate member 14 and the elongate member receivingportion 34 of the stabilization member 12. The annular rim 28, however,can limit the rotation of the stabilization member 12 by blocking thearms 38 from rotating further over the top of the head 20 of theelongate member 14. More particularly, as the stabilization member 12rotates relative to the head 20, the arms 38 can engage the annular rim28, which can prevent the stabilization member 12 from rotating furtherin that direction. The stabilization member 12 can rotate in alldirections relative to the elongate member 14 such that the central axisCA of the stabilization member 12 is at an angle α relative to a centrallongitudinal axis LA of the elongate member 14 in the range of about 0degrees to about 30 degrees. In other words, when the arms 38 of thestabilization member 12 are engaged with the annular rim 28, the centralaxis CA of the stabilization member 12 can be at an angle of about 30degrees relative to the longitudinal axis LA of the elongate member 14.

Other exemplary stabilization members are illustrated in FIGS. 3A and3C. As shown, stabilization members 12′, 12″ are provided and can have aplurality of expandable arms 38′, 38″ extending proximally from astabilizing plate portion 30′, 30″ and a plurality of bone engagingtines 42′, 42″ extending distally from the stabilizing plate portion30′, 30″. In the embodiment of FIG. 3A, the stabilizing plate portion30′ has an outer diameter substantially the same as an outer diameter ofthe expandable arms 38′. The outer diameter can be in the range of about8 mm to about 20 mm, and more preferably in the range of about 10 mm toabout 15 mm, for example, about 13 mm. As shown in FIG. 3B, thestabilizing plate portion 30 can have an outer diameter larger than anouter diameter of the expandable arms 38. The outer diameter of thestabilizing plate portion 30 can be in the range of about 10 mm to about25 mm, and more preferably in the range of about 13 mm to about 20 mm,for example about 16 mm. The stabilizing plate portion shown in FIG. 3Ccan have an outer diameter substantially larger than an outer diameterof the expandable arms 38″. The outer diameter of the stabilizing plateportion 30″ can be in the range of about 13 mm to about 30 mm, and morepreferably in the range of about 15 mm to about 25 mm, for example about19 mm. As will be appreciated by those having ordinary skill in the art,the stabilizing plate portions 30, 30′, 30″ and the expandable arms 38,38′, 38″ can have any diameter as desired relative to one another andrelative to an elongate member utilized therewith. The various exemplarystabilization members 12, 12′, 12″ can also have any height as desired.For example, a particular stabilization member 12, 12′, 12″ can have aheight in the range of about 1 mm to about 15 mm, and more preferablybetween about 5 mm to about 10 mm, for example, about 6 mm, 7 mm, 8 mm,9 mm, etc. As will be appreciated by those having ordinary skill in theart, the stabilization members 12, 12′, 12″ can be used with any of thevarious elongate members described herein.

Another embodiment of an elongate member 60 is illustrated in FIGS. 4Aand 4B. Similar to the elongate member 14 above, the elongate member 60can have a shank 62 extending distally from a substantially sphericalhead 64. The elongate member 60 can be cannulated with a lumen 66extending longitudinally therethrough, and the shank 62 can include athread 68 extending over at least a portion thereof. Further, the head64 can include an annular rim 70 extending proximally therefrom forlimiting rotation of a stabilization member (not shown). A proximalportion 72 of the head 64 can optionally include one or more slots 74formed therein to allow the head 64 to be expandable. In the illustratedembodiment, the head 64 includes four slots 74 formed through a sidewallof the head 64 and through the annular rim 70. The four slots 74 definefour arms 76 in the proximal portion 72 of the head 64 that can expandand contract around an opening 78 formed in the head 64.

While the opening 78 in the head 64 can have many configurations, in theillustrated embodiment, a distal portion of the opening 78 can beconfigured to receive a delivery tool to facilitate insertion of theelongate member 60 into bone. A proximal portion of the opening 78 canhave a thread 80 extending therearound such that the opening 78 isconfigured to receive a set screw 82 therein. The set screw 82 can be athreaded member that increases in diameter in a distal to proximaldirection such that as the set screw 82 is threaded into the opening 78,it expands the opening 78 due to its increasing width. When the elongatemember 60 is coupled to any of the stabilization members describedherein, threading the set screw 82 into the opening 78 in the head 64can cause the head 64 to expand and engage the stabilization member moresecurely. The set screw 82 can sit flush with a top surface 84 of theannular rim 70 or it can sit a distance below the top surface 84 of theannular rim 70. The set screw 82 can be cannulated with a lumen 86 thatcan align with the lumen 66 in the elongate member 60. The set screw 82can also have an opening 88 formed in a proximal surface thereof forreceiving a tool to facilitate insertion of the set screw 82 into theopening 78 in the head 64.

Any of the stabilization members and elongate members described hereincan include a bioactive fusion-promoting material capable of activelyparticipating in spinal fusion. The fusion-promoting material can be asurface morphology change, such as a roughened surface, to allow forbony ongrowth, or materials, such as titanium beads or meshes, can beadded to allow bony in-growth. In some embodiments, the stabilizationmember and/or the elongate member can be formed from a bioactivematerial, thereby allowing the implant to participate in spinal fusion.In other embodiments, the stabilization member or the elongate membercan include a portion (or a coating) formed from a bio-active fusionpromoting material. In addition, in any of the stabilization memberembodiments described herein, a cavity or opening formed within thestabilization member can be filled and/or packed with a bio-activefusion promoting material. The stabilization member shown in FIG. 3B caninclude a cavity 90 formed therein in which a bio-active fusionpromoting material can be packed. In other embodiments, an opening orcavity can be formed within an elongate member for the same purpose. Forexample, FIGS. 5A-6C and 7 illustrate various embodiments offusion-promoting elongate members, as will be described below.

The fusion-promoting bioactive material can include any material capableof actively participating in spinal fusion. In an exemplary embodiment,the bioactive material can be allograft bone material (such asAllowashed™ available from LifeNet, Inc.; Virginia Beach, Va.). Inanother example, the material can be a bioresorbable plastic(poly-lactic acid, polyglycolic acid, their derivatives and/or blends),poly-anhydride (PolymerDrug™ by PolyMerix, Piscataway, N.J.),polymerized sugars or starches (Eureka™ by Surmodics of Eden Prairie,Minn.), bioceramic (HIP Vitox™ alumina or Zyranox™ zirconia by MorganAdvanced Ceramics of Fairfield, N.J.; crystalline hydroxyapatite,tricalcium phosphates or combinations of these materials by BerkeleyAdvanced Biomaterials of San Leandro, Calif.), bioceramic-loadedbioabsorbable material, or dense protein (Novasilk™ by Protein PolymerTechnologies of San Diego, Calif.). Exemplary embodiments of suchbioabsorbable materials include Biocryl™ (an 85% PLA/PGA, 15% tricalciumphosphate material available from Depuy Mitek, a Johnson & JohnsonCompany; Raynham, Mass.) or TriABSorb™ (a 5% hydroxyapatite, 95% PLAmaterial available from Depuy Mitek, a Johnson & Johnson Company;Raynham, Mass.). Preformed plugs produced from TCP or HA. As anotherexample, the material can be an osseointegrating porous polymer such asPEEK/Optima™ (available from Invibio, Inc.; Greenville, S.C.). Thebioactive fusion promoting material can be autologus bone graftintra-operatively harvested from the patient. Those skilled in the artwill appreciate that any combination of these materials are within thespirit and scope of the present invention.

In one embodiment shown in FIG. 5, an elongate member 100 is providedhaving a shank 102 extending distally from a head 104. The elongatemember 100 can be cannulated with a lumen 103 and can be configured forbeing inserted into bone. The head 104 can have any shape andconfiguration, but in the illustrated embodiment, the head 104 has asubstantially spherical body with a flattened proximal top surface 106.An opening 108 can be formed in the head 104 to receive a driving toolto facilitate insertion of the elongate member 100 into bone. The shank102 can have at least one thread 110 extending therearound, and at leasta portion 112 of the shank 102 can remain unthreaded. A major diameterof the head 104 can be greater than a major diameter of the shank 102.

In some embodiments, the shank 102 can optionally include features topromote fusion. For example, the shank 102 can include a plurality ofopenings 114 formed through a sidewall thereof. While the openings 114can be any size and shape, in the illustrated embodiment there are fourcircular openings 114 that extend laterally through the shank 102 in adirection orthogonal to a central longitudinal axis of the elongatemember 100. The openings 114 can have a diameter less than a distancebetween two windings of the thread 110 so that each opening 114 can bepositioned between two windings. The openings 114 can be filled and/orpacked with a bio-active fusion promoting material that can encouragebone growth through the openings, thereby promoting fusion. The openings114 can be packed with the bio-active fusion promoting material throughthe lumen 103 and/or can be packed directly through the openings 114. Insome embodiments, the openings 114 can be formed within a proximalportion of the shank 102 that is disposed within the facet joint, asopposed to a distal portion of the shank 102 disposed within a pedicle.In this way, fusion between the facet faces is promoted through the useof the openings 114 filled with the bio-active composition.

Another exemplary elongate member 120 is illustrated in FIGS. 6A and 6B.As shown, the elongate member 120 can include a shank 122 extendingdistally from a head 124. The elongate member 120 can be cannulated witha lumen 126 extending therethrough and can be configured to be insertedinto bone. The head 124 can have any shape and configuration, but in theillustrated embodiment, the head 124 has a substantially spherical bodywith a flattened proximal top 128. An opening 130 can be formed in thehead 124 to receive a driving tool to facilitate insertion of theelongate member 120 into bone. The shank 122 can have at least onethread 132 extending therearound. In the illustrated embodiment, theshank 122 can have two portions with different diameters. A proximalportion 134 of the shank 122 can have a first major diameter D₁, and adistal portion 136 of the shank 122 can have a second major diameter D₂.In this case, the first major diameter D₁ is greater than the secondmajor diameter D₂ such that the larger first diameter D₁ can bepositioned between and/or within the facet joint faces, enabling theelongate member 120 to be stronger at this superficial location. Inaddition, the larger diameter D₁ can better enable joint stabilizationby acting as a “key” to prevent facet face sliding motion. Furthermore,in some embodiments, the proximal portion 134 with the larger diameterD₁ can have material removed from sidewalls thereof to enable a bonegraft cage configuration that will encourage bone growth through theelongate member 120 that spans the facet faces and provides furthermechanical stabilization of the facet joint. A major diameter of thehead 124 can be greater than the first and second major diameters D₁, D₂of the shank, although as will be appreciated by those having ordinaryskill in the art, the major diameter of the head 124 can also besubstantially the same as or smaller than the first major diameter D₁ orthe second major diameter D₂.

The shank illustrated in FIGS. 6A and 6B can also have features topromote fusion. As shown, the shank 122 can include various sized andshaped openings formed in a sidewall thereof. The shank 122 can include,for example, three openings spaced longitudinally along a length of theshank 122 that extend laterally through the body of the shank 122. Afirst opening 138 can be an oblong shaped opening that has a width lessthan a minor diameter of the shank 122 and a height that spans at leasttwo windings of the thread 132. A second opening 140 can also be anoblong opening positioned distal to the first opening 138, but with awidth greater than its height such that it can be positioned between twowindings of the thread 132. A third opening 142 can be a circularopening positioned distal to the first and second openings 138, 140 andhaving a diameter less than the space between two windings of the thread132. The openings 138, 140, 142 can be filled and/or packed with abio-active fusion promoting material that can encourage bone growththrough the openings 138, 140, 142, thereby promoting fusion.

As will be appreciated by those skilled in the art, any of the elongatemembers described herein can have any number of openings formed therein,in any configuration. For example, in addition to two opposing openingswithin a sidewall of a shank (i.e., one opening laterally extendingthrough the shank), there can be any number of openings formed around acircumference of the shank, such as in the elongate member illustratedin FIG. 12A. A plurality of openings can be formed around thecircumference of a shank, positioned between windings of the thread,such that there are, for example, 3, 4, 5, 6, 7, 8, 9, 10, or moreopenings formed around a circumference of the shank. These openings canhave any desired shape and size. Further, any number of openings can bepositioned longitudinally along a length of the shank of the elongatemember.

Another exemplary elongate member 150 is illustrated in FIG. 7, and issimilar to that shown in FIGS. 6A and 6B with a shank 158 extendingdistally from a head 162. Three laterally extending openings 152, 154,156 can be formed along a length of the shank 158 in a proximal portion164 thereof for receiving a bio-active fusion promoting material. Inthis embodiment, however, a distal portion 160 of the shank issubstantially longer than the proximal portion 164. When inserted into afacet joint, the distal portion 160 can extend into the pedicle whilethe proximal portion 164 is engaged with the facet joint. Anchoringwithin the pedicle in this way provides the elongate member 150 withgreater stability within the facet joint.

The elongate members illustrated in FIGS. 1A-7, and any other elongatemember embodiments described herein, can have any particular dimensionas needed for a particular procedure or anatomy. For example, aparticular elongate member can have a length from a proximal end to adistal end in the range of about 20 mm to about 80 mm. Generally, theelongate members shown in FIGS. 1A-6B can have a length in the range ofabout 25 mm to about 45 mm, and more preferably in the range of about 30mm to about 40 mm, for example about 30 mm or about 35 mm. Generally,the elongate member shown in FIG. 7 can have a length in the range ofabout 50 mm to about 70 mm, and more preferably in the range of about 55mm to about 65 mm, for example 60 mm. A greater diameter of the shanks,including the proximal and the distal portions of a shank that changesdiameter, can range from about 2 mm to about 15 mm, more preferably fromabout 4 mm to about 10 mm, for example, about 5 mm, 6 mm, 7 mm, 8 mm, 9mm, etc.

Various stabilization members for use with the various elongate membersare also provided and can be configured in various alternative shapesand sizes as compared to those substantially circular embodimentsdiscussed above. The stabilization members can be configured to includedifferent types of bone engaging features, including bone engagingtines, serrated/cutting edges, and extension portions, as well asdifferent shaped and sized bone engaging members disposed on onestabilization member. In addition, a particular stabilization member canbe configured to include at least one lateral extension that can be inthe form of a “plate-like” configuration, resulting in a substantiallyoblong, rectangular, and/or oval shaped stabilization member. In otherembodiments, laterally extended stabilization members can becurvilinear, both laterally and longitudinally. Such embodiments can beutilized in either intra-facet and/or trans-facet stabilization of thefacet joint. As will be discussed, a laterally extended configurationallows for broader engagement across the facet joint so that thestabilization member makes contact with bony anatomy adjacent to thefacet joint, such as the lamina, lateral facet, or pedicle. This allowsthe stabilization member to span the facet to secure, stabilize, andfuse the facet faces. In some embodiments, a laterally extendedstabilization member can be bendable to provide closer and morecomplementary engagement across a facet joint.

FIGS. 8A-8B illustrate an embodiment of a stabilization member 180having an extended lateral profile. The stabilization member 180 canhave an elongate member receiving portion 182 with an opening 184 formedtherethrough for receiving a head of an elongate member (not shown). Thestabilization member 180 can also have an extension portion 184 with anopening 186 formed therethrough. The two portions 184, 186 can beseparated by a bend zone region 188 formed in a stabilizing plateportion 190 of the stabilization member 180. The bend zone region 188can be a thinned portion of the stabilizing plate portion 190 thatallows the stabilizing plate portion 190 to be flexible in that regionsuch that the stabilization member 180 can be bent around a facet jointor other boney surface to provide better conformation thereto.

The structure of the stabilization member 180 can be substantially thesame as described above relative to the substantially circularstabilization members. A plurality of expandable arms 192 can extendproximally from the stabilizing plate portion 190 in a substantiallycircular configuration defining the opening 184 through the elongatemember receiving portion 182. As shown, a central axis of the opening184 can be offset from a central axis of the stabilization member 180.The expandable arms 192 can be configured to receive a substantiallyspherical head of an elongate member. A plurality of bone engaging tines194 can extend distally from the oblong shaped stabilizing plate portion190 around its outer perimeter such that the bone engaging tines 194 arealso in an oblong or oval shape. In this way, when the stabilizationmember 180 is bent along its bend zone region 188, the tines 194 willengage bone around the entire perimeter of the stabilizing plate portion190.

FIGS. 9A and 9B illustrate an exemplary stabilization member 180′substantially identical to that shown in FIGS. 8A and 8B, except with alonger extension portion 184′. The stabilization members 180, 180′ shownin FIGS. 8A-9B can have any length as needed for a particular procedureor for a use in a particular anatomy. For example, the stabilizationmembers 180, 180′ can have a length in the range of about 10 mm to about35 mm, more preferably in the range of about 15 mm to about 30 mm, forexample, about 17 mm, 18 mm, 19 mm, 20 mm, 21 mm, 22 mm, 23 mm, 24 mm,25 mm, 26 mm, etc.

In another embodiment illustrated in FIGS. 10A and 10B, a stabilizationmember 200 is provided. The stabilization member 200 can be extendedlaterally such that a stabilizing plate portion 202 of the stabilizationmember 200 is substantially oblong and/or oval. Similar to theembodiments described above, the stabilization member 200 can have anelongate member receiving portion 204 with an opening 206 formedtherethrough and a plurality of expandable arms 208 extending proximallytherefrom in a substantially circular configuration for receiving asubstantially spherical head of an elongate member. As shown, a centralaxis of the opening 206 can be offset from a central axis of thestabilization member 200. The stabilization member 200 can also have anextension portion 210.

The stabilizing plate portion 202 can have a plurality of bone engagingtines 212 extending distally therefrom around a perimeter thereof. Inthis embodiment, the bone engaging tines 212 can have an asymmetricconfiguration in which one or more of the tines have a length and/orangular configuration different than a length and/or angularconfiguration of at least one other of the tines 212. This can providefor better purchase within bone and can allow variable placement, forexample, into the lamina or adjacent to a mammillary process. As shown,the stabilizing plate portion 202 can have an extension portion 213extending distally from one lateral side thereof configured, forexample, to extend into a pedicular valley. The extension portion 213can have, for example, one or more bone engaging members extendingtherefrom that are disposed distally and angularly. As shown, two boneengaging tines 212 a are angled relative to the other tines 212, and twobone engaging tines 212 b are formed at a distal end of the extensionportion 213 and are thus substantially greater in length than the othertines 212. The extension portion 213 can provide the stabilizationmember 200 with a more aggressive engagement into the bone and thus amore secure purchase therein.

The bone engaging tines 212 can be arranged in many different ways, andin the illustrated embodiment, the tines 212 can each terminate in sucha way as to form an overall curved configuration relative to thestabilizing plate portion 202, as shown in FIG. 10A. The shorter tines212 can have any desired shape and configuration, but in the illustratedembodiment, they have a configuration the same as that described abovewith an outer surface 214 angled toward a central axis of thestabilization member 200 and a bone piercing and/or penetrating tip 216formed at the distal end. The angled tines 212 a can have a non-angledouter surface 214 a with angled bone piercing and/or penetrating tips216 a. Further, the longer tines 212 b can have an angled inner surface218 with a non-angled outer surface 214 b and bone piercing and/orpenetrating tips 216 b at their distal end. The extension portion 213can have a length from the stabilizing plate portion 202 in the range ofabout 10 mm to about 20 mm, more preferably in the range of about 13 mmto about 18 mm, for example about 15 mm. A width of the stabilizationmember can be the same as described above for the embodiment shown inFIGS. 8A-9B.

A further embodiment of a stabilization member 230 is illustrated inFIGS. 11A-11D. In this embodiment, the stabilization member 230 can havea repositioning mechanism and/or adjustable coupling configured to allowtranslation of an elongate member 232 in at least one direction relativethereto. The stabilization member 230 can be extended laterally suchthat its length is longer than its width, and it can accommodate amovable translation plate 234, shown most clearly in FIG. 11D, tofacilitate translation of the elongate member 232. A stabilizing plateportion 236 of the stabilization member 230 can have a substantiallyrectangular opening 238 formed therein to receive the translation plate234 and can define rails 240 on which the translation plate 234 canslide. The translation plate 234 can therefore have a widthsubstantially the same as the width of the stabilizing plate portion236, but a length shorter than the length of the stabilizing plateportion 236 so that it can translate lengthwise. A plurality ofexpandable arms 242 can extend proximally from the translation plate 234and can define an opening 244 for receiving a head 246 of the elongatemember 232. A diameter of the opening 244 can be substantially the sameas the width of the translation plate 234 and the stabilizing plateportion 236, as shown in FIG. 11D.

Four sidewalls can define an outer perimeter of the stabilizing plateportion 236 and can terminate distally in a plurality of bone engagingtines. Two opposing sidewalls 248, 250 can be symmetric and can have anumber of different length tines 252 arranged in a curved configurationas shown in FIGS. 11A and 11C. The opposed symmetric sidewalls 248, 250can extend proximally a distance above the stabilizing plate portion 236in a curved configuration to define sidewalls for the rails. The othertwo opposing sidewalls 252, 254 can be asymmetric and can haveasymmetric bone engaging tines formed at a distal end thereof. One ofthe asymmetric sidewalls 252 can extend distally in a curvedconfiguration such that the sidewall 252 forms an arc outward from thestabilizing plate portion 236 and then inward toward a central axis ofthe stabilization member 234 terminating in two distal bone engagingtines 256 and two side bone engaging tines 258. The bone engaging tines256 formed at a distal end of the sidewall 252 can have a lengthsubstantially greater than the lengths of the other bone engaging tines252, 258. The other asymmetric sidewall 254 can extend distally at anangle relative to the stabilizing plate portion 236 such that thesidewall 254 is angled away from the central axis of the stabilizationmember 230, rather than being orthogonal to the central axis, as withthe symmetric sidewalls 248, 250, or angled toward the central axis, aswith the other asymmetric sidewall 252.

In use, the translation plate 234 coupled to the elongate member 232 cantranslate relative to the stabilizing plate portion 236 in a directionparallel with the opposing symmetric sidewalls 248, 250 or orthogonal tothe opposing asymmetric sidewalls 252, 254. For example, in someembodiments, the translation plate 234 can translate by a distance inthe range of about 5% to about 40% of a length of the stabilizationmember 230. In an embodiment in which the length of the stabilizationmember 230 is about 16 mm, the translation plate 234 can translate about4 mm (about 25%) in each direction. As will be appreciate by thoseskilled in the art, the stabilization member 230 can have any length asneeded for a particular procedure and/or to fit a particular anatomy.

Another exemplary embodiment of an implant 260 is illustrated in FIGS.12A-12E. In this embodiment, the implant 260 can include a laterallyextended stabilization member 262 configured to receive both an elongatemember 264 and a fixation screw 266. A stabilizing plate portion 268 ofthe stabilization member 262 can be substantially oblong and/or oval. Afirst side 270 of the stabilizing plate portion 268 can have an opening272 formed therethrough defined by a plurality of expandable arms 274extending proximally from the stabilizing plate portion 268 andconfigured to receive a substantially spherical head 276 of the elongatemember 264 therein. The opening 272 can be configured to allow polyaxialrotation of the elongate member 264 relative to the stabilization member262. A second side 278 of the stabilizing plate portion 268 can have anopening 280 formed therethrough configured to receive the fixation screw266. A diameter of the opening 280 can be smaller than a diameter of theopening 272. As with previous embodiments, a plurality of bone engagingtines 282 can extend distally from the stabilizing plate portion 268around a perimeter of the stabilizing plate portion 268.

One or more bend zone regions 284 can be disposed between the first andsecond sides 270, 278. The bend zone regions 284 can be thinned portionsof the stabilizing plate portion 268 that are flexible and thus able tobe bent such that each of the first and second sides 270, 278 can bedisposed at a different angle in bone relative to one another. This canallow the implant 260 to be more versatile and to more easily engagewith a wider variety of bone surfaces and anatomies.

Any of the elongate members described herein can be disposed within theopening 280 in the first side 270 of the stabilizing plate portion 268.Further, while any type of elongate member can be used within theopening 272 in the second side 278 of the stabilizing plate portion 268,in the illustrated embodiment, the lamina fixation screw 266 isutilized. The fixation screw 266 can have a flattened head 286 with ashank 288 extending distally therefrom. The shank 288 can have a thread290 disposed therearound and can have a diameter that decreases in aproximal to distal direction. The use of the fixation screw 266 with theelongate member 264 can provide a more secure and stable attachment tobone. For example, while the elongate member 264 is disposed within thefacet joint, the fixation screw 266 can be disposed within the lamina toprovide a more secure attachment for the elongate member 264. Further,the stabilizing plate portion 268 can be bent along its one or more bendzone regions 284 so that the stabilization member 262 can more closelyform to the anatomy of the bone.

Another embodiment of an implant similar to that in FIGS. 12A-12E, andhaving a repositioning mechanism and/or adjustable coupling associatedtherewith, is illustrated in FIGS. 13A and 13B. A stabilization member300 is provided having first and second sides 302, 304, each side 302,304 configured to receive one of a fixation screw 306 and an elongatemember 308. In this case, however, a bend zone region 310 is in the formof a “T key” with one side 312 being in the shape of a T and the otherside 314 having a complementary shape for receiving the T. The bend zoneregion 310 can be bendable, as well as laterally adjustable, and canthus be expanded laterally and/or bent to fit a particular anatomy. Aswill be appreciated by those skilled in the art, any shaped interlockingconfiguration can be used in the bend zone region 310 to facilitatelateral adjustment of the region.

FIGS. 14A-14D illustrate another embodiment of an implant having arepositioning mechanism and/or adjustable coupling. As shown, astabilization member 320 is provided having a slotted opening 322 formedtherethrough. A plurality of bone engaging members 324 can extenddistally therefrom for engaging a bony surface, and a plurality of teeth326 can be formed in a proximal surface thereof for engagingcorresponding teeth in a head 330 of an elongate member 332, shown inFIG. 14C. The elongate member 332 can have a substantially flattenedhead 330 with a distal surface having a plurality of teeth 328 forengaging the teeth 326 formed in the proximal surface of thestabilization member 320. A shank 334 can extend distally from the head330. When the elongate member 332 is disposed within the slotted opening322 in the stabilization member 320, it can be moved laterally to adesired position along the member 320. Engagement between the teeth 326,328 prevent further movement once positioned. In some embodiments, thestabilization member 320 can be bendable along its slotted opening 322to facilitate attachment to a variety of bony surfaces and anatomies.

The above implant embodiments can be formed of any suitable materialknown in the art. A particular stabilization member and elongate membercan be formed of the same material or of different materials. Inaddition, different portions of a particular stabilization member orelongate member can be formed of different materials. In someembodiments, the implant or a portion thereof can be formed fromtitanium or a titanium alloy, polyether ether ketone (PEEK), ceramic,316 stainless steel, CoCr, trabecular metals, zirconia, crystallinehydroxyapatite, TCP, poly-lactic acid & poly-glycolic acid and blendsthereof, etc. In other embodiments, the implant or a portion thereof,can be formed of Nitinol. The temperature characteristics of Nitinol canallow the stabilization member and/or the elongate member to expand orcontract when disposed in bone to facilitate better placement andsecurement with a particular location, as well as to reduce loosening ofthe implant once implanted.

The various implant embodiments disclosed herein can generally beutilized to provide fixation and/or fusion to a facet joint. The variouselongate members described herein can be delivered into a facet joint,and in some embodiments, can be anchored into the pedicle for addedfixation. The various stabilization member embodiments described hereincan be used to mechanically co-join the facet faces. An overview offacet joint anatomy and prior art methods of providing spinal fixationto a facet joint can be found in U.S. Patent Application No.2008/0255622, filed on Apr. 13, 2007 and entitled “Facet Fixation andFusion Screw and Washer Assembly and Method of Use,” which isincorporated by reference in its entirety.

In use, an exemplary elongate member coupled to an exemplarystabilization member can be provided for insertion into a facet joint.The elongate member and/or the stabilization member can optionally bepacked with, formed from, or and/or coated with a bio-active fusionpromoting composition. The insertion procedure can preferably beperformed minimally invasively, although it can be performed using anysurgical procedure now in use or yet to be. The elongate member andstabilization member can be delivered into and secured within and aroundthe facet joint and pedicle in a number of ways. For example, in someembodiments, the implant can be inserted using various trajectories thatstart in intra-facet (between the facet faces) or trans-facet (throughthe facet faces) and subsequently pass close to the centroid of thepedicular bone that connects the vertebral body to the lamina. Moreparticularly, the elongate member can be placed in between the facetfaces in an intra-facet pedicular trajectory, as shown in FIG. 15B, orcan be placed in a trans-facet trajectory, as shown in FIG. 15A. Inother embodiments, the implant can be inserted using varioustrajectories that do not start within or pass through the facet jointbut pass close to the centroid of the pedicular bone that connects thevertebral body to the lamina, including entry into the lateral aspect ofthat facet or entry directly into the pedicle. For example, the implantcan be placed into the pedicle valley in a traditional pediculartrajectory, as shown in FIG. 15C, and/or it can placed into themammillary process.

While there are a number of different ways in which rrthe implant can bedelivered to the facet joint, in one embodiment, the stabilizationmember can be delivered to the facet joint first, before delivery of theelongate member. An opening can be formed within the patient and aguidewire can be inserted using fluoroscopy and other conventionaltechniques. Serial dilation can be performed to provide access throughtissue to the facet joint. An opening for the elongate member can bedrilled into, within, or near the facet joint at the desired insertiontrajectory. The stabilization member can be delivered to the facet jointarea for sizing, followed by awling of any securement features. Thestabilization member can then be secured to the desired anatomy bypiercing the bone with the bone engaging members. If the stabilizationmember has bending features, lateral extensions, or other additionalsecurement features, they can be manipulated and/or utilized to provideadditional engagement and stabilization. For example, a portion of thebone engaging members of the stabilization member can engage an outerportion of the facet of a first vertebra and another portion of the boneengaging members can engage an outer portion of the facet of a second,adjacent vertebra. The stabilization member can be bent around theseportions and/or laterally adjusted to an appropriate length forengagement with these portions. Once the stabilization member issecured, the elongate member can be inserted through an opening withinthe stabilization member and into the predrilled opening within,through, or around the facet joint. In some embodiments, a set screw canbe placed into an opening within a head of the elongate member to expandthe head into tighter interlocking engagement with the stabilizationmember. In other embodiments, the stabilization member and the elongatemember can be delivered to and implanted within or around the facetjoint as a coupled implant using the above-described techniques.

The implants described herein can be used, for example, in facet volumerestoration procedures and/or partial correction of coronal planedeformity (scoliosis) at one or more vertebral levels. This enables theimplant to be used as a fusion device and permits deformity correctionat one or more levels. Further, the implant can be used for thoracicspine facet joint fusion and deformity correction, and can also assistin deformity correction when used with mono-portal transforaminal lumbarinterbody fusion (TLIF) and posterior lumbar interbody fusion (PLIF) tocorrect disc height lost, coronal deformity, and foraminal volume loss.The implants can further be used in other procedures such as posteriorstabilization for an anterior lumbar interbody fusion (ALIF 360),reduction of low-grade spondylolisthesis, or terminal fusion of diseasedand painful facet joints.

In some embodiments, a system or kit is provided and can include one ormore of the exemplary implants, stabilization members, and/or elongatemembers described herein. In addition, the system or kit can include oneor more tools that permit delivery and insertion, as well as somelongitudinal distraction of the facet joint. Any of the stabilizationmember and elongate member embodiments disclosed herein can be includedin such a system or kit and can be fully interchangeable with oneanother.

One skilled in the art will appreciate further features and advantagesof the invention based on the above-described embodiments. Accordingly,the invention is not to be limited by what has been particularly shownand described, except as indicated by the appended claims. Allpublications and references cited herein are expressly incorporatedherein by reference in their entirety.

What is claimed is:
 1. A spinal implant, comprising: a cannulatedelongate member having a first bone engaging portion with a firstdiameter and a second bone engaging portion with a second diameterdisposed distal to the first bone engaging portion, the first boneengaging portion being configured for insertion into a facet joint andthe second bone engaging portion being configured for insertion into apedicle, at least one of the first and second bone engaging portionshaving at least one opening formed in a sidewall thereof and configuredto receive an osteoconductive composition; and a stabilization memberconfigured to seat the elongate member, the stabilization member havinga first expandable portion configured to engage a proximal portion ofthe elongate member in a snap-fit configuration and a second boneengaging portion having a plurality of bone engaging tines extendingtherefrom, each bone engaging tine being angled toward a central axis ofthe elongate member, wherein the first diameter is greater than thesecond diameter.
 2. The spinal implant of claim 1, wherein at least oneof the first and second bone engaging portions has a plurality ofopenings formed in the sidewall thereof.
 3. The spinal implant of claim2, wherein each of the plurality of openings is a different shape. 4.The spinal implant of claim 1, wherein the elongate member includes aproximal head with a shank extending distally therefrom, the shankhaving a thread extending over at least a portion of thereof.
 5. Thespinal implant of claim 1, wherein the first expandable portioncomprises a plurality of substantially flexible arms arranged in acircular configuration, each arm being separated from adjacent arms by aslit configured to allow expansion and contraction of the arms.
 6. Thespinal implant of claim 5, wherein the plurality of substantiallyflexible arms are configured to receive a proximal head of the elongatemember and to allow rotation in all directions of the proximal headrelative thereto.
 7. The spinal implant of claim 1, wherein thestabilization member includes a lateral extension such that a centralaxis of the first expandable portion is offset from a central axis ofthe stabilization member.
 8. The spinal implant of claim 7, wherein thelateral extension is configured to bend relative to the first expandableportion to conform to a bony surface adjacent to a facet joint as theelongate member is positioned within the facet joint.
 9. A spinalimplant, comprising: an elongate member having a proximal head and abone engaging shank extending distally from the proximal head, theproximal head being configured for rotational movement in all directionswithin a stabilization member, the shank further having a threadextending over at least a portion thereof, and a proximal portion with afirst major diameter and a distal portion with a second major diameter,wherein the first major diameter is greater than the second majordiameter; and a stabilization member configured to seat the elongatemember, the stabilization member having a plurality of expandable armsextending proximally therefrom, the expandable arms configured toreceive the proximal head in a snap fit connection.
 10. The spinalimplant of claim 9, the shank having at least first and second openingsformed in a sidewall thereof and being configured to receive anosteoconductive composition, wherein the first and second openings aredisposed along a longitudinal axis of the elongate member; wherein atleast one of the first and second openings are foamed the portion of theshank having the thread.
 11. The spinal implant of claim 10, wherein thefirst and second openings have different shapes.
 12. The spinal implantof claim 9, wherein the stabilization member includes a stabilizingplate portion having a plurality of bone engaging tines extendingdistally therefrom for piercing bone.
 13. The spinal implant of claim12, wherein the stabilizing plate portion has a length extending betweenfirst and second opposed sides and a width extending between third andfourth opposed sides, wherein the length is greater than the width. 14.The spinal implant of claim 13, wherein the stabilizing plate portionincludes an extension member extending distally from one of the firstand second opposed sides, the extension member having a length greaterthan a length of the plurality of bone engaging tines.
 15. The spinalimplant of claim 13, wherein the stabilizing plate portion includes atleast one bendable region disposed thereon such that the stabilizingplate portion is bendable along a line orthogonal to the length of thestabilizing plate portion.
 16. The spinal implant of claim 13, whereinthe stabilization member further includes a translation plate disposedadjacent to the stabilizing plate portion and having a plurality ofexpandable arms extending proximally therefrom configured to receive theproximal head of the elongate member and to allow rotational movement ofthe proximal head in all directions relative to the stabilizationmember.
 17. The spinal implant of claim 16, wherein the translationplate is configured to translate laterally with the elongate memberrelative to the stabilizing plate portion along the length of thestabilizing plate portion.
 18. The spinal implant of claim 13, whereinthe expandable arms extend proximally from the stabilizing plate portionand define a first opening disposed adjacent to one of the first sideand the second side and offset from a central axis of the stabilizingplate portion.
 19. The spinal implant of claim 18, further comprising asecond elongate member, and wherein the stabilizing plate portionincludes a second opening formed on the first or second side opposite tothat of the first opening, the second opening configured to receive thesecond elongate member therethrough.
 20. The spinal implant of claim 19,wherein the second elongate member is a lamina screw configured toengage a lamina while the elongate member is engaged within a facetjoint.
 21. The spinal implant of claim 13, wherein the stabilizing plateportion includes a first portion and a second portion, the first andsecond portions being coupled together by an adjustable coupling. 22.The spinal implant of claim 21, wherein the adjustable coupling isconfigured to allow translation of the first portion relative to thesecond portion and bending of the first portion relative to the secondportion.
 23. A method of implanting a spinal implant, comprising:providing an elongate member having a first bone engaging portion and asecond bone engaging portion, at least one of the first and second boneengaging portions having at least one opening formed therein forreceiving an osteoconductive composition; packing an osteoconductivecomposition into the opening; surgically delivering the elongate memberinto a vertebra such that the first bone engaging portion is disposedwithin a facet joint and the second bone engaging portion is disposedwithin a pedicle; penetrating a stabilization member, coupled to theelongate member, into a bony portion of a vertebra; wherein penetratinga stabilization member, coupled to the elongate member, into a bonyportion of a vertebra further comprises engaging a bony portion of avertebra adjacent to the facet joint in which the elongate member isdisposed; and surgically delivering a lamina screw to a vertebral laminathrough an opening in the stabilization member to provide additionalstabilization for the elongate member disposed within the facet joint.24. The method of claim 23, further comprising bending the stabilizationmember to engage a bony portion of a vertebra adjacent to the facetjoint in which the elongate member is disposed.
 25. The method of claim23, further comprising delivering a first spinal implant to a firstfacet joint and a second spinal implant to a second, corresponding facetjoint at the same level of a spine.
 26. The method of claim 23, whereinthe surgically delivering step is conducted in a minimally invasivesurgical procedure.